Mixed media:
Painted in Photoshop.

As a starter the ref. character was one of the default naked female Poser 5 models. Never used a 3Dm model as base before and I guess there isnt much left of the original, except for the the "doll-like" stiffness :P which maybe is quite suitable here...

The bg is partly made in Illustrator and reworked/finished in Photoshop.
I havent use any other particular references than googled lots of vintage ads of food, drinks and so forth...just love the vintage style